In recent years, cellular structures have attracted great deal of attention of many researchers due to their unique properties like exhibiting high strength at low density and great energy absorption. Also, the applications of cellular structures (or lattice structures) such as wing airfoil, tire, fiber and implant, are mainly used in aerospace, automotive, textile and biomedical industries respectively. In this investigation, the idea of using cellular structures in pipes made of acrylonitrile butadiene styrene (ABS) material was focused on and four different pipe types were designed as honeycomb structure model, straight rib pattern model, hybrid version of the first two models and fully solid model. Subsequently, these models were 3D printed by using FDM method and these lightweight pipes were subjected to compression tests in order to obtain stress-strain curves of these structures. Mechanical properties of lightweight pipes like elasticity modulus, specific modulus, compressive strength, specific compressive strength, absorbed energy and specific absorbed energy were calculated and compared to each other. Moreover, deformation modes were recorded during all compression tests and reported as well. The results showed that pipe models including lattice wall thickness could be preferred for the applications which don’t require too high compressive strength and their specific energy absorption values were notably capable to compete with fully solid pipe structures. In particular, rib shape lattice structure had the highest elongation while the fully solid one possessed worst ductility. Lastly, it is pointed out that 3D printing method provides a great opportunity to have a foresight about production of uncommon parts by prototyping.

On the road to real applications, although there are lots of efforts focusing on mechanical and physical features in the literature, their machining abilities were examined in a very limited manner. In this study, machining properties of pumice reinforced AA7075 syntactic foams manufactured via the newly offered sandwich infiltration technique were investigated by performing face turning. Physical and microstructural (optical and SEM works) analyses were conducted on fabricated foams to carry out sample characterization. All machining forces were measured for different cutting speeds (25, 50, and 100 m/min) and feed rates (0.05, 0.10, and 0.15 mm/rev). After the turning operation, areal surface roughness values were measured using a 3D surface profilometer and material removal rate (MRR) values were calculated. Besides, chip mixtures including pumice and metal fragments were collected to probe chip morphology in detail. The results showed that machining forces were affected by the operation parameters differently, and the lowest surface roughness was detected at the cutting speed of 100 m/min and 0.05 mm/rev feed rate. Furthermore, the shape of the metal chips changed from long/continuous characteristic to saw-tooth morphology depending on increasing cutting speed levels while pumice particles exhibited breakaway tendency as the feed rates went up.

Additive manufacturing (AM) is a versatile and promising method for rapid prototyping and advanced design applications. Owing to its unique potential for fast production rates, and capacity of creating complex shapes, the number of researches on AM techniques have increased day by day in the technical literature. In this work, contrary to common literature efforts focused on mechanical properties, friction and wear behaviors of additively manufactured PETG samples were analyzed experimentally. As a methodology, fused filament fabrication (FFF) was selected. In order to explore the influence of manufacturing factors on wear properties, layer thickness (0.1, 0.2, and 0.3 mm), infill rate (40, 60, 80, and 100%), and building direction (vertical and horizontal) were changed. Before the friction tests, dimensional accuracy, hardness, and surface roughness measurements were conducted to interpret better the wear results. In addition, macroscopic and microscopic inspections were performed to determine the correct reason behind the deformation. From the data collected during the tests, there was a positive interaction between volume loss and layer thickness. Besides, there was no direct interaction between infill rate/building direction and coefficient of friction. In comparison with vertically built samples, horizontally built samples were subjected to more plastic deformation, and their worn surfaces were severely damaged.

Selective laser melting (SLM) is a three-dimensional (3D) printing process that can manufacture functional parts with complex geometries as an alternative to using traditional processes, such as machining wrought metal. If precision and a high surface finish are required, particularly for creating miniature channels or geometries smaller than 1 mm, the fabricated parts can be further machined. Therefore, micro milling plays a significant role in the production of such miniscule geometries. This experimental study compares the micro machinability of Ti-6Al-4V (Ti64) parts produced via SLM compared with wrought Ti64. The aim is to investigate the effect of micro milling parameters on the resulting cutting forces (Fx, Fy, and Fz), surface roughness (Ra and Rz), and burr width. In the study, a wide range of feed rates was considered to determine the minimum chip thickness. Additionally, the effects of the depth of cut and spindle speed were observed by taking into account four different parameters. The manufacturing method for the Ti64 alloy does not affect the minimum chip thickness (MCT) and the MCT for both the SLM and wrought is 1 μm/tooth. SLM parts exhibit acicular α martensitic grains, which result in higher hardness and tensile strength. This phenomenon prolongs the transition zone of micro-milling for the formation of minimum chip thickness. Additionally, the average cutting force values for SLM and wrought Ti64 fluctuated between 0.072 N and 1.96 N, depending on the micro milling parameters used. Finally, it is worth noting that micro-milled SLM workpieces exhibit lower areal surface roughness than wrought ones.

In recent years, additive manufacturing (AM) technologies have become greatly popular in the polymer, metal, and composite industries because of the capability for rapid prototyping, and appropriateness for the production of complex shapes. In this study, a comprehensive comparative analysis focusing on the influence of post-processing types (heat treatment and water absorption) on tensile and impact responses was carried out on 3D printed PETG, PLA, and ABS. In addition, layer thickness levels (0.2, 0.3, and 0.4 mm) were selected as a major production parameter and their effect on mechanical properties was combined with post-processing type for the first time. The results showed that both tensile and impact resistance of the printed polymers increased thanks to the heat treatment. The highest tensile strength was measured for heat-treated PLA, while the peak impact endurance level was reached for heat-treated PETG. Also, water absorption caused a mass increment in all samples and induced higher tensile elongation values. Decreasing layer thickness had a positive effect on tensile features, but impact strength values dropped. On the other hand, all samples were subjected to macro and micro failure analyses to understand the deformation mechanism. These inspections indicated that for impact samples straight crack lines converted to zigzag style separation lines after the heat treatment. As for the tensile samples, the exact location of the main damage zone altered with the production stability, the water absorption capacity of the polymer, and the thermal diffusion ability of the filament.